This invention relates generally to seals and, more particularly, to structures for retaining seals in a desired position.
In turbomachine structures, it is necessary to provide sealing means between stationary and rotating components and, in some cases, between two stationary components which are susceptible to relative radial movement. One such interface is that between a nozzle support structure and a shroud support hanger immediately downstream thereof. The nozzle support structure is relatively fixed in its radial position but is susceptible to thermal growth and shrinkage as it is exposed to the hot airstream on its inner side and to the cooling airstream on its outer side. The shroud support hanger, on the other hand, is designed to be more sensitive to predetermined thermal growth patterns in order to accommodate thermal and mechanical growth of the rotor and thereby decrease the clearance between the shroud and the rotor structure. It is thus common to place a seal in axial relationship between the nozzle support and the shroud support hanger so as to allow the relative radial movement between the two elements while preventing the flow of high pressure cooling air from the outer side thereof to the hot gas stream on the inside thereof.
Problems which have been associated with such a seal application include that of assuring installation of the seal during the initial assembly procedure and that of insuring that when the system is disassembled for purposes of maintenance and repair, for example, the seal remains in its place or is replaced during the reassembly procedure. Present methods include the use of clips or pins or a combination of the two, any of which may be unreliable, complicated in assembly, and expensive.
It is therefore an object of the present invention to provide an improved method and apparatus for retaining an annular seal.
Another object of the present invention is the provision for a seal retaining structure which does not require the use of clips and/or pins.
Yet another object of the present invention is the provision for a seal retaining structure which is simple in construction, reliable in use and relatively inexpensive to fabricate.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.